That's not a good yes or no question, because it not only unites two different points together, but also really depends on your definition of global warming, and also ties a lot of other different issues into it. You could for example believe that humanity affects climate to some extent, but still think that it's not bad enough to support environmentalists from economics point of view. You could also believe that this climate change is real, but is not caused by human activity and is just a part of a natural process.
I just don't think that boxing a complex issue into a boolean is a good idea.